<script>
onload = function() {
  scroller.scrollTop = 200;
}
</script>
<style>
.composited {
  /* Triggers promotion and creates a stacking context */
  will-change: transform;
}

#scroller {
  overflow: scroll;
  height: 200px;
  width: 200px;
}

.container {
  height: 500px;
  background: red;
}

.relative {
  position: relative;
  top: 225px;
  height: 50px;
  background: green;
}
</style>
<div id="scroller" class="composited">
  <div class="container">
    <div class="relative"></div>
  </div>
</div>
